Anti-5 caC

The so-called 6th base, 5 hydroxymethylcytosine has been discovered in 2009. The function of this new modified base remains mostly unclear, but it is certain that the 5 hmC base is generated by enzymatic conversion of 5 methylcytosine(5 mC) into 5 hydroxymethylcytosine by the TET family of oxygenases. Early reports suggested that 5 hmC may represent an intermediate of active demethylation in a new pathway which demethylates DNA, converting 5 mC to cytosine. Recent evidence fuel the hypothesis that 5 hmC represents an intermediate, which could involve further oxidation of the hydroxymethyl group to a formyl or carboxyl group followed by either deformylation or decarboxylation. The carboxyl and formyl groups of 5 formylcytosine (5 fC) and 5 carboxylcytosine (5 caC) could be enzymatically removed without excision of the base.